With the rapid development of the mobile terminal technology, various mobile terminals such as mobile phones are widely used. Functions of the mobile terminals are constantly increased, and these new functions bring many conveniences to users, and thus are well received by users. For example, an existing mobile phone has a fingerprint recognition virtual key, and a user may make fingerprint recognition by touching the virtual key.
At present, the fingerprint recognition virtual key is configured in such a way that a fingerprint recognition sensor is disposed beneath a glass cover-plate, and the fingerprint recognition sensor recognizes a fingerprint when the user's finger touches the area that the fingerprint recognition sensor locates. However, the fingerprint recognition sensor has different sensitivity in different cases; for example, a noise signal of a mobile phone in different charging states may affect a signal of the fingerprint recognition sensor in recognizing the finger. Therefore, when a finger touches the fingerprint recognition virtual key at different instances, the fingerprint recognition sensor may acquire different fingerprint signals. However, since the fingerprint recognition generally adopts a fixed threshold value, a fingerprint recognition circuit may have unstable fingerprint recognition rates.